Apparatus for drying molds and cores.



No. 722,312. PATENTED MAR. l0, 1903.

` W. L. MARS.

APPARATUS FOR DRYING MOLDS AND CORES. v

n APPLIOATION FILED MAY 19. 1902. xoMoDEi.. v s SHEETS-SHEET 1.

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PATENTBD MAR. 10, 1903`.

l W. L. MARS. APPARATUS FOR DRYING MOLDS AND CORI-IS.

APPLIUATION `FILED MAY 19, 1902.

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APPARATUS FOR DRYING MOLDS AND GORES.

APPLIOATION FILEDl MAYV 191Y 1902.

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WILLIAM L. MARS, OF BUFFALO, NEW YORK.

APPARATUS FOR DRYING MOLDS AND CORES.

SPECIFICATION forming part of Letters Patent No. 722,312, dated March10, 1903.

Application iiled May 19, 1902. Serial No. 107,949. (No model.)

To @ZZ 1072/077?, it may concern:

Beit known that I, WILLIAM L. MARS, a citizen of the United States,residing at Buffalo, in the county of Erie and State of New York, haveinvented new and useful Improvements in Apparatus forDrying Molds andCores, of which the following is a specification. Y

This invention relates to an apparatus designed more particularly fordrying the molds and cores employed in casting pipes, such as water andgas pipes. As is well known in this art, such molds and cores arecomposed principally of sand or earth and coated with pulverized coal orblackiug to protect the sand and cause the molten metal to flow freelyin casting. Before being dried the molds and cores contain considerablemoisture, and unless the evaporated moisture or steam produced in dryingthem is carried off as rapidly as the same is formed it condenses orcauses sweating of the molds and cores. i/Vhen this occurs, the waterwashes oif the blacking or coating of the mold, particularly at itslower end, where the usual enlargement or bell of the mold forms achannel in which the Water collects before the mold is fully dried. Uponpouring molten metal into such a mold the metal cuts the exposed portionof the sand lining and some of the sand becomes incorporated with themetal, thereby scabbing the casting and rendering the same unt forhigh-pressure service.

The object of my invention is to provide an efficient drying apparatuswhich will quickly and completely carry off the moisture of the moldsand cores, so that sweating and scabbing cannot take place and allliability of producing inferior castings is avoided.

In the accompanying drawings, consisting of three sheets, Figure l is afront elevation of the furnace. Fig. 2 is a vertical longitudinalsection of the drying apparatus, the plane of the section being in line2 2, Fig. 4. Fig. 3 is a detached sectional elevation of the retardingdevices, which control the action of the dampers. Fig. 4 is a horizontalsection in line d 4, Fig. 3. Fig. 5 is a horizontal section of theapparatus in line 5 5, Fig. 2. Fig. 6 is a fragmentary vertical sectionin line 6 6, Fig. l, on an enlarged scale. Fig. 7 is a transversevertical section of a modified construction of the apparatus designedmore especially for drying cores.

Like letters of reference refer to like parts in the several figures.

Referring to the construction', shown in Figs. l to 6, A indicates afurnace of anysuitable or approved construction located above thesurface of the ground and having its fire or combustion chamber Aprovided with the usual door A2 and its ash-pit A3 with a draftdamperA4. The combustion-chamber is provided in its side walls above thegrate` with air-inlet apertures b,which communicate with longitudinalflues B, arranged on opposite sides ofthe furnace and extendingthroughout its length, as shown in Fig. 5. These Iiues are provided intheir front walls with air-inlet openings, which are controlled bycheckdampers B'.

C indicates an oven or drying-chamber which communicates with thecombustionchamber of the furnace and in which the molds D to be driedare placed in an upright position, as shown in Fig. 2. The molds areintroduced at the top of the oven, which is normally closed by aremovable cover E. The top of the oven is preferably about on a levelwith the top of the furnace, and the oven is slinken a sufcient distancebelow the surface of the ground to bring the top of the molds a shortdistance above the bridge-wall of the furnace. The oven may be extendedlaterally on opposite sides of the furnace to increase its capacity,that shown in the drawings being large enough to receive twelve molds ata time.

F indicates Ventilating-pipes, which rise through the bottom of the ovenO and with which the central apertures d of the seats d' and sockets d2of the molds are adapted to register, as shown in Fig. 2. ing-pipe isprovided for each mold, and the several pipes are connected by branchpipes f With a main Ventilating pipe or liue F, which latter isconnected with or terminates in a chimney F2. draft through the severalVentilating-pipes F, the main Ventilating-line F is tapered toward theend farthest from the chimney, as shown by dotted. lines in Fig. 5. Thearea of the largest or discharge portion of this main flue is equal tothe aggregate area of the sev- Such a ventilaty In order to equalize the1 IOO eral branch pipes connected therewith. The

oven is provided with a number of additional ventilating-pipesf2, whichopen into the same between the molds for carrying olf the moisture inthe oven outside of the molds. In the drawings three of such auxiliaryventilating-pipes are shown, which are connected directly to the mainflue F. The top or cover E of the oven is tight or imperforate to eX-clude the outer atmosphere at this point and avoid weakening of thedraft through the oven, and the combustion-chamber of the furnace opensinto the upper portion of the oven adjacent to the cover, so that thehot air and products of combustion upon issuing into the ovenimmediately enter the adjacent upper ends of the molds. By thisconstruction and arrangement of the drying apparatus a downward draft ofthe products of coinbustion and hot air from the furnace is created fromthe top of the oven through the tubular molds resting on its bottom, asindicated bythe arrows in Fig. 2, the hot air and products of combustionpassing thence through the various Ventilating and branch pipes Fff intothe main flue F and escaping finally through the chimney. The molds areby this means quickly dried, and the steam or evaporated moisture iswithdrawn from the oven before condensation can take place. Allliability of washing the molds and proy ducing defective castings istherefore avoided.

Heretofore the furnace has been located in a pit and the oven has beenarranged above the furnace, the products of combustion ascending throughperforations in an iron plate which forms the top of the furnace and thebottom of the oven. This plate soon burns out and requires frequentrenewal. The arrangement of the furnace below the surface of the groundis also objectionable, because it requires the fuel to be lowered andthe ashes to be elevated. By arranging the furnace on the surface of theground and extending the oven below the surface the plates abovereferred to are dispensed with and the laborious handling of the fueland ashes incident to such a sunken furnace is obviated. Owing to therapid withdrawal of the moisture effected by this apparatus, the same isespecially desirable for drying molds in which the bell or enlargementis at the bottom; but the apparatus is equally useful for drying moldsin which the bell is at the top.

In order to insure an ample air-supply and a thorough and uniformventilation of the oven, the furnace is preferably provided with anautomatic regulating device, which operates to open the draft-damper A4and close the check-dampers B when fresh coal is supplied to the furnaceand gradually closes the draft-damper and opens the check-damper whenthe iire gets under way. This regulating device is constructed asfollows: H indicates a double-acting dash-pot or cylinder securedvertically to the front wall of the furnace adjacent to the hinged sideof the fueldoor A2 and containing a tightly-fitted piston h. This pistonhas rods h' h2, which extend through stuffing-boxes at opposite ends ofthe cylinder. The latter is provided at opposite sides with longitudinalpassages or by-passes t' fi', which open at their upper ends into thetop of the cylinder and at their lower ends into valve-chambers i2 i3,which communicate with the bottom of the cylinder by ports 1141'5,respectively. One of these by-passes, which will hereinafter be termedthe free bypass, is comparatively large to permit apractically-unrestricted flow of the oil or other liquid through thesame in one direction. The valve-chamber of this by-pass contains anautomatic check-valve i, which closes upwardly against a valve-seat atthe lower end of the corresponding by-pass for checking the upward ow ofthe liquid from the portion of the cylinder below the piston into saidbypass when the piston descends, but permitting the free downward flowof the liquid through said by-pass into the bottom of the cylinder whenthe piston ascends. The upward ow of the liquid from the bottom of thecylinder through the other by-pass t', hereinafter termed the restrictedby-pass, is controlled by a hand or regulating valve 117, applied to thelower end of said pass and extending through a stuffing-box]l at thelower end of the cylinder. This regulating-valve is adjustable towardand from its seat, and for this purpose its stem is preferablyscrewthreaded and engaged with a screw-thread in the bore of thestufing-boxj, as shown in Fig. 3. By adjusting this valve more or lessclosely to its seat the upward passage of the liquid through therestricted by-pass is retarded accordingly and the descent of the pistonis retarded in the same measure.

K indicates a vertically-swinging quadrant or lever fulcrumed on ahorizontal stud 7c, projecting from the front wall of the furnace andhaving its upper arm pivotally connected with the lower piston-rod h2.The same arm of the lever is provided with a weight c, which tendsconstantly to lower the piston in the cylinder H.

L indicates a vertically-swinging shifting arm mounted on the stud 7oand adapted to strike against lugs or shoulders Z, arranged on the lowerarm or portion of the quadrantshaped lever K. The free lower end of thisshifting arm is connected with a lugm of the fuel-door by a link m. Thislug projects forwardly beyond the pintles of the doorhinges, as shown inFig. 5, so that upon opening the door the shifting arm is swunglaterally away from the door and caused to strike the shoulder Z of thelever K, thereby reversing the latter from the position shown in Fig. 1to that shown in Fig. 3 and raising the piston in the cylinder I-I. Uponclosing the fueldoor the shifting arm L is withdrawn from the shoulderof said lever, allowing the lever to return to its former position underthe action of its weight. In order to prevent bind- IOO IIO

ing of the connections between the fuel-door and the piston, thecylinder is mounted to oscillate on trunnions h3, carried by a yoke Il.This yoke is secured to the front of the furnace.

N indicates a transverse rock-shaft supported ou the front wall of thefurnace above the horizontal pintles of the draft-damper A4. This shafthas an actuating-arm n for rocking it and a second arm n, with which thedraft-damper is connected by a link n2. A second transverse rock-shaft 0is arranged on the front wall of the furnace above the checkdampers Bfor operating the latter. This shaft has an actuating-arm o and arms 02,with which the verticallyswinging checkdampers are connected by links03. Both of the rock-shafts N and 0 are operated by a cord or chain p,secured to the weighted lever K, as shown at p. The ends of this cordare secured to the actuating-arms n and 0 of the two rock-shafts, andthe upper portion of the cord is doubled around a guide-pulley q forrocking the shafts in opposite directions and causing the check-dampersto be closed when the'draft-damper A1 is opened, and vice versa.

It will now be understood that upon opening the fuel-door to feed thefurnace the shifting lever L takes part in the movement of the door andstrikes the shoulder Z of the quadrant-lever K, thereby reversing thelatter and elevating the piston 71.. By this movement the cord p ispulled and caused to turn the lower rock-shaft N in the proper directionto open the draft-damperA, and at the same time the upper portion of thecord is slackcned, allowing the check-dampers B to close by gravity.After feeding the furnace the fueldoor is closed, this movement of thedoor returning the shifting lever L to its former position withoutaffecting the position of the quadrant-lever K and the parts connectedtherewith. By the upward movement of the piston hthe liquid above thesame Was transferred to the portion of the cylinder below the piston,the same being forced downward through the free by-pass t' and past thecheckvalve is. In the absence of the retarding device the elevatedweight of the quadrant-lever K by its tendency to descend wouldimmediately lower the piston and reverse the position of the draft andcheck dampers; but inasmuch as the return of the liquid to the upperside of the piston is retarded by the constriction in the by-pass t" thepiston is allowed to descend, but very slowly, under the action of theweight, and hence after the fuel-door has been closed the draft-damperis slowly and gradually closed and the checkdampers are as graduallyopened. The descent of the piston is so timed by means of theregulating-valve l that the check-dampers are not fully opened nor thedraft-dam per fully closed until the fresh charge of fuel burnsbrightly. By this improved regulating device an abundant volume of airis supplied to the drying-oven under all conditions and a thoroughventilation of the oven is insured at all times. In order to supply auniform quantity of air regardless of whether the draft-damper or thecheck-dampers are open, the area of the draft-damper is about equal tothe aggregate area of the checkdampers.

When my improved apparatus is employed for drying cores, the same ispreferably modiiied, as shown in Fig. 7. In this case the oven, as wellas the furnace, is located above the surface of the ground, and when twoovens are employed, as shown, the furnace is arranged between the same.The ovens communicate with the combustion-chamber .by passages rr. Thecores S are supported horizontally on trucks or carriages running upontracks laid on the bottom of the ovens. F3 F4 indicate the mainVentilating-line and the Ventilating-pipes connected therewith andopening into the bottom of the ovens, preferably between the tracks. Inthis form of the apparatus a downdraft is created through the ovens, asin the apparatus first described.

I claim as myinventionw l. In an apparatus for drying molds and cores,the combination of an oven having a closed or imperforate top, a furnacehaving its combustion-chamber in direct communication with the upperportion of the oven and provided on opposite sides of said chamber withlongitudinal air-inlet fines which communicate with the chamber', a mainventilating-pipe, and branch pipes connected with said main pipe andextending through the bottom of the oven, substantially as set forth.

2. In an apparatus for drying molds and cores, the combination of anoven having a closed or imperforate top, a furnace having itscombustion-chamber in direct communication with the upper portion of theoven, a main Ventilating-pipe arranged underneath the oven, connected atone end with a stack or chimney and constructed of gradually-decreasingdiameter from thestack toward its opposite end, and branch pipesconnected with different portions of said main ventilating-pipe andopening through the bottom of the oven, substantially as set forth.

fitness my hand this 15th day of May, 1902.

WILLIAM L. MARS.

Witnesses:

THEO. L. Polar, CARL F. GEYER.

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